The following shows the daily heat emission profile of a typical summer day and a typical winter day
The following are the definition of heat emission components.
| variable | EnergyPlus output |
|---|---|
| emission.exfiltration | Environment:Site Total Zone Exfiltration Heat Loss [J](Hourly) |
| emission.exhaust | Environment:Site Total Zone Exhaust Air Heat Loss [J](Hourly) |
| emission.ref | SimHVAC:Air System Relief Air Total Heat Loss Energy [J](Hourly) |
| emission.rej | SimHVAC:HVAC System Total Heat Rejection Energy [J](Hourly) |
| emission.surf | Environment:Site Total Surface Heat Emission to Air [J](Hourly) |
The following shows the daily heat emission in the original scale. We can see a lot of large outliers. This indicates a large variability across different grid cells (500m x 500m).
The following plot zooms in to the non-outlier part of the boxplot
above. We can see the total heat emission peaks around noon time.
The following plot shows the daily heat emission by different
component and time of day for a typical summer day (7/15) and a typical
winter day (1/15). Surface heat emission is dominating and is much
larger than other components
The following plots the non-surface heat emission components.
Zooming in to the non-outlier parts. Among the non-surface heat
emissions, HVAC rejection heat is the largest. Different from surface
heat emission, the HVAC emission peaks around 3pm in the afternoon and
lingers around much longer.
Each data point in the following plot is the heat emission of a grid cell (or census tract) during a specific hour of day, averaged across a particular month. It compares the diurnal profile of the total heat emission and several heat emission sources.
The following plot shows the hourly average heat emission for each
heat emission component and for each month
The following zooms in to the non-outlier part.
The following plot shows the average hourly heat emission further
averaged across different grids or census tracts
The following plot shows the average hourly heat emission of each
component further averaged across different grids or census tracts
The following plot shows the total heat emission across grid cells at 2pm and 10pm for summer and winter and for weekday and weekend.
## Reading layer `wrf-grids-origin' from data source
## `/Users/yujiex/Dropbox/workLBNL/EESA/code/im3-wrf/high res grid for reporting/wrf-grids-origin.geojson'
## using driver `GeoJSON'
## Simple feature collection with 130176 features and 3 fields
## Geometry type: POLYGON
## Dimension: XY
## Bounding box: xmin: -119.0324 ymin: 33.09492 xmax: -116.8525 ymax: 34.76695
## CRS: 4326
## Reading layer `la-county-boundary' from data source
## `/Users/yujiex/Dropbox/workLBNL/EESA/code/im3-wrf/domain/la-county-boundary.geojson'
## using driver `GeoJSON'
## Simple feature collection with 7 features and 17 fields
## Geometry type: MULTIPOLYGON
## Dimension: XY
## Bounding box: xmin: -118.9446 ymin: 32.79521 xmax: -117.6464 ymax: 34.8233
## CRS: 4326
The following shows the surface component
The following plot shows the HVAC rejection component. HVAC rejection
have less day-night difference than building surface heat rejection.